A new international consortium was launched this week to investigate the probability of an impact on Earth by one of the tens of thousands of Near Earth Objects (NEO) currently being tracked, and to investigate several potential options for collision prevention. The project, known as NEOShield, will be headed by the German Space Agency (DLR) in partnership with research institutions in five different countries, the Russian space agency, and the British, French, and German offices of EADS Atrium.
“Over the next three and a half years [NEOSheild] will investigate the measures that can be employed to prevent near-Earth objects such as asteroids and comets from colliding with Earth,” said DLR officials in a statement following the project kick-off. Rusty Schweickart, former astronaut and past chairman of the B612 Foundation, praised the international aspect of the consortium. “[NEOShield] is being done by an international group of participants. This will be key, in the end, to insure that the results are widely accepted.”
The consortium will investigate the three currently most promising methods of asteroid deflection: kinetic impactors, gravity tractors, and thermonuclear blasts.
- Kinetic impactors have been proposed to prevent an asteroid impact by intentionally ramming it to alter its course away from Earth. A mission concept of this type, named “Don Quijote” was developed in 2005 in the ESA Concurrent Design Facility (CDF). The Don Quijote mission proposed to deflect the asteroid Apophis using two separate probes, one that would ram the asteroid at over 48,000 kilometers per hour, and another that would orbit Apophis to monitor the effects of the impact.
- Gravity tractors have been proposed as an alternative way to deflect asteroids without physically contacting them. In this concept, a probe would remain along side the asteroid, using the (albeit small) added gravity of the probe to gradually drag the asteroid off course. To remain in this position, however, several technical issues need to be resolved, including the development of a propulsion system (potentially ion thrusters) that could operate reliably and continuously for up to 10 years.
- Nuclear detonations on or near the surface of an asteroid could be used as a method to deflect asteroids, and could be particularly useful if the time between detection of an asteroid and the time until impact is too short for kinetic impactors or gravity tractors to be effective. The Russian portion of the NEOShield project will be investigating how an asteroid may respond to a nuclear detonation, and potential contingency scenarios in which the detonation is ineffective at completely deflecting the object. However, the use of nuclear devices in space is a particularly sensitive topic both politically and legally; Alan Harris, NEOShield project leader at DLR, emphasized that “[NEOShield] does not advocate testing nuclear explosives in space and will not be studying nuclear weapons technology.”
The NEOShield program is being financed by the European Comission, which has committed roughly 4 million euros to the program. Although it will not develop the actual technology required for collision avoidance, the program is viewed by many as an important first step in eventually preventing catastrophic NEO impacts. “The development of a ‘game plan’ […] is distinct from executing the ‘game plan’. But without having thought through the options, criteria, triggering elements and such ahead of time, no action will ever be taken,” said Schweickart. “Developing the game plan will be necessary much more frequently than actually executing it.”
The video below shows an animation of ESA’s Don Quijote kinetic impactor concept.